Unraveling the mystery of the cosmological constant: Does spacetime uncertainty hold the key?(a)

In addressing the cosmological constant problem, we propose that the discrepancy between the theoretical and observed values can be ascribed to the inherent uncertainty in the spacetime metric. Mach's principle, which posits that mass shapes spacetime, intersects with quantum mechanics’ description of a particle as a quantum cloud, rendering the precise location of a particle's mass unknowable. Consequently, understanding spacetime structure at the quantum level becomes elusive. This connection between quantum and spacetime uncertainty could hold the key to resolving the cosmological constant problem. Intriguingly, the length scale of spacetime uncertainty, aligns with the macroscopic quantum weirdness observed in recent experiments. The spacetime uncertainty can be quantified by the scale factor in the Friedmann-Lemaître-Robertson-Walker (FLRW) universe.